1. Field of the Invention
The present invention relates to a forceps stopper for an endoscope for preventing a pressure leakage from an inlet of a channel through which a treatment tool is inserted.
The present disclosure relates to the subject matter contained in Japanese Patent Application No. Hei. 10-66521 filed on Mar. 17, 1998, which is incorporated herein by reference in its entirety.
2. Description of the Related Art
A forceps stopper of an endoscope usually has a seal member that is an elastic material, in which a closure such as a slit or the like is formed so that the closure can be spread open by means of a treatment tool to be inserted into the closure. The seal member can assume many and diverse shapes.
The treatment tools inserted into the forceps stopper for the endoscope include a forceps, a snare, a syringe, a basket and a contrast medium supply tube and the like. Such treatment tools are roughly classified into two groups, in which one uses a metallic coil pipe as a shaft and the other uses a flexible tube made of a synthetic resin.
The coil pipe has comparatively high stiffness and problems are less likely to occur when it is inserted into or detached from the forceps stopper.
On the other hand, the flexible tube does not have enough stiffness so that the flexible tube would bend by pass resistance thereof and become no longer functional when the treatment tool is passed through the slit formed in the seal member of the forceps stopper. This problem cannot be completely solved by use of the slit or other closure forming means because if the slit or the like is not formed which can be tightly closed, it is afraid that a pressure leakage would occur at an inlet of a channel through which the treatment tool is inserted.
In various seal members used today, the pressure leakage easily occurs in a seal member formed by rubber sheets having a slit formed across their thickness.
In the case of using seal members in the form of an O-ring that are squeezed in the axial direction until the hole portion is almost closed, a pressure against the passage of a treatment tool is so high that its sheath might easily bend.